Using a "Yes/No" prompt in a For loop

I'm trying to write code where the user would select a case that contains different amounts of money. They get three attempts. However, if they like the amount they got before the third attempt they can stop at that point and the program terminates.

I'm having trouble figuring out the syntax for creating a prompt that asks them if they want to continue and they answer with "y" or "n". If they answer "y" it stays in the loop, if "n", it breaks out of the loop and the program terminates.